Technical information

23 EqualLogic Configuration Guide | Version 15.2 | August 2014
7 Capacity planning
7.1 RAID 6 drive layouts and total reported usable storage
RAID 6 (striped set with dual distributed parity) combines N disks in an arrangement where each stripe
consists of N-2 disks capacity for data blocks and two disks capacity for parity blocks. Each parity block
generates parity using a different view of the data blocks depending on the RAID 6 implementation. RAID 6
can tolerate up to two drive failures per RAID stripe set at the same time without data loss. RAID 6 is not
recommended for workloads consisting mainly of random writes. Using a RAID 6 policy, Table 6 shows
the drive layouts that are enforced based on the number of drives in each array/hot spare configuration,
and the total usable storage available for each model.